<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Title</title>
</head>
<style>
    body{
        margin: 0;
        padding: 0;
    }
    .container{
        width: 100%;
        height: 700px;
        background-color: #bfa;
        margin-top: 100px;
        display: grid;
        grid-template-rows: 207px 155px 259px;
        grid-template-columns: 420px 365px 299px calc(420px - 302px) 296px ;
        justify-content: center;
        grid-template-areas:
                'a b d d f'
                'a b e g g'
                'a c e g g'
        ;
        gap: 5px;
    }
    .item:nth-child(1){
        grid-area: a;
        background-color: #5500ff;
    }
    .item:nth-child(2){
        grid-area: b;
        background-color: red;
    }
    .item:nth-child(3){
        grid-area: c;
        background-color: #00aeec;
    }
    .item:nth-child(4){
        grid-area: d;
        background-color: #cccccc;
    }
    .item:nth-child(5){
        grid-area: e;
        background-color: yellowgreen;
    }
    .item:nth-child(6){
        grid-area: f;
        background-color: green;
    }
    .item:nth-child(7){
        grid-area: g;
        background-color: #ff6700;
    }
</style>
<body>
<div class="container">
    <div class="item">1</div>
    <div class="item">2</div>
    <div class="item">3</div>
    <div class="item">4</div>
    <div class="item">5</div>
    <div class="item">6</div>
    <div class="item">7</div>
</div>
</body>
</html>
